Heretofore, in the injection molding of the above referenced interior trim parts, three component parts were generally involved in the formation of the finished product.
Typically, a preformed grained vinyl shell has been made from dry thermoplastic powder particles which are applied to a heated shell mold from a powder box to form a continuous monochromatic one-piece shell. See U.S. Pat. No. 4,784,911.
The resultant vinyl shell is then fitted into a pour mold, covering the entire inner exposed surface of the mold. Thereafter, a suitable liquid expandable foam material, including a suitable adhesion material, is poured onto the surface of the vinyl shell either prior to covering the pour mold with a cover, or through a pour opening formed in the closed cover.
A mounting insert or substrate backing material is detachably mounted on the inner surface of the cover, such that is becomes bonded to the foam material once the latter has expanded to fill the entire cavity intermediate the vinyl shell and the cover, thus forming the finished product.